Silencer or muffler and method of producing same



J. R. HALL Aug. 13, 1968 SILENCER OR MUFFLER AND METHOD OF PRODUCINGSAME Filed April 26, 1967 4 Sheets-Sheet 1 IN VENTOR. JAMES R H441.

Maw

Aug. 13, 1968 J. R. HALL 4 Sheets-Sheet 2 Filed April 26, 1967 INVENTOR.H JAMES R HALL -fl-..........-.,, A T TO/PA/5V m 99 e 6 a u 59 6 a J. R.HALL Aug. 13, 1968 SILENCER OR MUFFLER AND METHOD OF PRODUCING SAMEFiled April 26, 1967 4 Sheets-Sheet 5 INVENTOR- JAMES A? //ALL 47 ram/5y 8- 1968 J. R. HALL 3,396,813

SILENCER OR MUFFLER AND METHOD OF PRODUCING SAME- Filed April 26, 1967 4Sheets-Sheet 4.

INVENTOR. JAMES A2 HALL Arrow/5y United States Patent 3,396,813 SILENCER0R MUFFLER AND METHOD OF PRODUCING SAME James R. Hall, Toledo, Ohio,assignor to Oldberg Manufacturing Company, Grand Haven, Mich., acorporation of Michigan Filed Apr. 26, 1967, Ser. No. 633,900 16 Claims.(Cl. 181-61) ABSTRACT OF THE DISCLOSURE the ends of the rnufiler andbeing adjustable to varying angularities, the spherical regions of thebushings or nipples being welded to the ends of the mufiier shell.

The present invention relates to silencers or muffiers and method ofproducing same, the silencers or mutilers being particularly adapted forattenuating sound waves of exhaust gas streams from internal combustionengines of automotive vehicles. Sound attenuating muffler constructionshave heretofore been fashioned with tubular outer shells with ends orend headers secured to the shells and bushings inserted in openings inthe end headers and secured by welding or other suitable means.

In such constructions the bushings were necessarily disposed on an axiscoincident or parallel with the longitudinal axis of the shell. Thechassis of an automotive vehicle with which the mufiler may be usedusually embodies several reinforcement or structural members and theengine exhaust conveying system including the sound attenuating deviceor mufiler must be fashioned to avoid interference with componentsof'the chassis construction. With prior muffler constructions whereinthe bushings were aligned or parallel with the axis of the mufiler, manyinstallations required special singularly-arranged end regions of theexhaust pipe and tailpipe requiring special bending of the exhaust pipeand tailpipe to accommodate a mufiler or silencer. Such arrangements arecostly and necessitate extensive fabricating operations.

The present invention embraces the provision of a silencer or mufflerconstruction embodying a tubular outer shell of one-piece constructionfashioned with smoothly curved dome-shaped end regions of progressivelyreducing diameter, the terminals of the end regions defining circularopenings to accommodate spherically-shaped regions of coupling membersor bushings welded to the reduced end regions of the mufiler shell.

The invention embraces a method of fabricating a muffler involvingprogressively reducing an end region of a tubular shell to define acircular opening at the terminus of the reduced region, fitting aspherically-shaped portion of a coupling member into the opening,adjusting the angular position of the member relative to the shell, andwelding the reduced end of the mufller to the spherically-shaped portionof the fitting.

Another object of the invention is the provision of a mufllerconstruction embodying a one-piece muffler shell having dome-shaped endportions or sections terminating in circular openings arranged toaccommodate gas inlet and outlet coupling members or bushings havingballshaped portions extending into the openings wherein one or bothbushings provide support means for tubular gas passage means disposed inthe mufiler shell and fashioned with perforations forming acoustic orsound attenuating couplings with the surrounding chamber for attenuatingsound Waves.

Another object of the invention resides in a one-piece mufiler shellconstruction having curved end regions of progressively reduceddiameter, each end region terminating in a circular edge defining anopening to receive a member having a ball-shaped configuration wherein aseal is effected by welding the circular terminal edge of the mufiler tothe ball-shaped configuration of the member throughout thecircumferential region of engagement.

Another object of the invention resides in a one-piece mufiier shellhaving an end section of progressively decreasing diameter terminatingin a circular edge defining an opening, the opening adapted toaccommodate a spherically-shaped portion of a coupling elementadjustable to a desired angle and the element welded to the end regionof the shell throughout the circular edge region.

Further objects and advantages are within the scope of this inventionsuch as relate to the arrangement, operation and function of the relatedelements of the structure, to various details of construction and tocombinations of parts, elements per se, and to economies of manufactureand numerous other features as will be apparent from a consideration ofthe specification and drawing of a form of the invention, which may bepreferred, in which:

FIGURE 1 is a side elevational view, partly in section, of one form ofmufiler construction illustrating coupling members insingularly-arranged positions with respect to the mufiler shell;

FIGURE 2 is an elevational view, partly in section, of a portion of themuffler construction shown in FIGURE 1 with a coupling member in axiallyaligned relation with the mufiler axis;

FIGURE 3 is an end elevational view of the arrangement shown in FIGURE2;

FIGURE 4 is an elevational view showing a portion of a mufiierconstruction illustrating a coupling member angularly arranged withrespect to the longitudinal axis of the mufiler;

FIGURE 5 is an elevational view, partly in section, of a portion of amuffler similar to FIGURE 2 illustrating a modified form of couplingmember in angularly-arranged position relative to the mufiler shell;

FIGURE 6 is a longitudinal sectional view of a portion of a mufllershell and coupling member assembly wherein the coupling member providessupport for a gas passage tube;

FIGURE 7 is a fragmentary sectional view of a muffler constructionembodying a gas passage tube having a portion disposed in an end openingand welded to the muffler shell and a coupling member secured to anextremity of the gas passage tube;

FIGURE 8 is a longitudinal sectional view of a muffler constructionillustrating a coupling member arranged to provide support for one endof a gas passage tube;

FIGURE 9 is a longitudinal sectional view of a form of mufilerconstruction wherein the couplings support a perforated gas passagetube, and

FIGURE 10 is a longitudinal sectional view of a portion of a mufllershell and coupling member assembly illustrating the gas passage tubeextending into the coupling member.

Referring to the drawings in detail and initially to the constructionshown in FIGURES 1 through 3, the sound attenuating or muffierconstruction 10 is inclusive of an outer shell 12 of one piece of metalfashioned of generally cylindrical tubular shape in which is disposed acylindrically-shaped gas passage tube 14 of lesser diameter than theshell 12 and having a comparatively large number of openings 16 whichform acoustic couplings with the elongated annular sound attenuatingchamber 18 between the gas passage tube 14 and the shell 12.

In the form shown in FIGURES 1 and 2, spaced partitions 20 and 22 ofannular shape are disposed in spaced relation lengthwise of the shell12. Each of the partitions is fashioned with an inner flange 24 definingan opening in which is snugly fitted the gas passage tube 14 which may,if desired, be welded to one or both of the flanges. Each partition isprovided with a peripheral flange 26 which is snugly fitted into theinterior of the shell 12.

As illustrated in FIGURES 1 and 2, the end regions are of dome shape andin the method of fabrication the assembly of gas passage tube andpartitions 20 and 22 is disposed within the cylindrical tubular shell 12before the end region-s thereof are reduced in dimension to domeshapedconfiguration.

A feature of the invention is the provision of a onepiece mufiier shell12 which is of tubular shape and cylindrical throughout its length priorto the reduction in dimension of its end regions. The shell 12 is ofsheet metal of the seamless tube type or a tube of the Welded seam type.As shown in FIGURE 1, the end sections or regions 30 and 32 areconfigurated with an inward taper but each end region is smoothly curvedand of gradually decreasing diameter from the cylinder portion to theend or terminus 34 to form a dome shape.

The curved end sections or regions 30 and 32 of the shell maybe swagedto dome shape by means of swaging dies, or the metal at these sectionsmay be spun inwvardly to the configuration illustrated in the drawings.Thecurved end sections or rounded end regions of the shell may befashioned by utilizing a tube of smaller diameter for the shell andexpanding the tube to a larger diameter With rounded or dome-shaped endregions. This may be accomplished by employing a cavity mold or dieshaped to the exterior configuration of the mufiler shell and expandingthe tube wall outwardly by polyurethane forming. The terminus of eachend section is a circular edge defining a circular opening, the circularor terminal edge 34 of the opening lying in a plane normal to thelongitudinal axis of the tubular shell 12. By reason of the sWa-ging orspinning operations in progressively reducing the end regions orsections of the muffler shell to a dome shape, the metal may beprogressively thickened slightly.

The invention embraces the provision of a nipple, bushing or couplingfor each end of the mufiier shell joined to the terminus of the reducedend portions of the muffler shell. The couplings or bushings 38 and 40for the ends of the mufiler shell are of generally similar construction.As shown in FIGURES 1 and 2, the bushing 38 is of a character for use atthe gas inlet end of the muffler and comprises a generallytubular-shaped member of circular cross section having a central orintermediate portion 42 which is integrally joined with an adjacentcylindrical end region 44 of slightly larger internal diameter than theportion 42 to receive the end region of an exhaust pipe or exhaustconveying tube connected with the exhaust system of an internalcombustion engine.

The exhaust pipe (not shown) is telescoped into the cylindrical portion44 and a clamp means (not shown) of conventional construction surroundsthe portion 44 near its end region. The Wall of the portion 44 near theend thereof is provided with a plurality of slots 48 to enable the clampto draw the end regions of the portion 44 into tight engagement 'with anexhaust pipe. The coupling or bushing 38 is fashioned at its oppositeend with a spherically-shaped portion 50 of a diameter to be snuglyreceived within the circular opening defined by the terminal region ofthe reduced portion 30 of the muffier shell.

As the exterior configuration of the portion 50 is spherical or ballshaped, the coupling member 38 may be adjusted to various angularpositions with respect to the longitudinal axis of the muffler shell 12.

As shown in FIGURE 1, both the inlet and outlet couplings or bushings 38and 40 are angularly-"trranged with respect to-the longitudinal axis ofthe shell 12. The circular terminal edge 34 defining the opening in thedomeshaped portion 30 of the mufiier shell is welded as at 52 in acircular path throughout the circumference of the ball shape portion 50to provide a gas tight seal between the muffler shell 12 and thecoupling 38, the welding further serving to maintain the predeterminedangular relationship of the coupling 38 With respect to the shell.

The coupling or bushing 40 at the gas outlet end of the mufiler isfashioned with a cylindrical portion 56, and a tailpipe (not shown) maybe telescoped over the exterior of the cylindrical portion 56 andconventional clamp means may be provided embracing the tailpipe to drawthe latter into a snug engagement with the portion 56. Adjacent theportion 56 is a cylindrical region 60 of a diameter slightly larger thanthe portion 56 providing an abutment or shoulder 62 to limit thelengthwise position of the tailpipe telescoped over the portion 56. Thecoupling or bushing 40 is fashioned with a spherically-shaped portion 64of a diameter to be snugly received within the circular terminal edgeregion 34 of the curved portion 32 of the muffler.

FIGURES 2 and 3 illustrate a portion of the mufiier 10 and the inletcoupling or fitting 38 showing the axis of the coupling aligned with theaxis of the muffier. It is to be understood that the outlet coupling 49may likewise be arranged whereby its longitudinal axis is aligned withthe axis of the muffler 10 in the same manner.

As particularly shown in FIGURE 1, the curved end regions or dome-shapedregions 30 and 32 of the muffler shell 12 are smoothly curved andprogressively reduced in diameter toward the circular terminal edges 34,the edges defining circular openings in the ends of the shell. Thecircular edge regions 34 snugly receive the ballshaped configurations 50and 64 of the respective couplings 38 and 4t) and the edges 34 arewelded to the peripheries of the ball-shaped configurations of thecouplings by the vcircular welds 52 and 66 coincident with the edges 34.The curved or dome-shaped portions 30 and 32 of the mufiler shell arepreferably of a configuration as illustrated in FIGURE 1 but it is to beunderstood that the particular shape of curvature may be varied ormodified dependent upon the length of space desired between the headersor partitions 20 and 22 and the end couplings 38 and 40, the diameter ofthe muffler shell, and the diameters of the couplings or bushings 38 and40.

An important feature of the construction is that each curved portion 30and 32 terminates in a circular edge 34 so that when the edge regionsare welded to the couplings as at 52 and 66, the Welds will be circularas they are coincident with the edges. These structural featuresfacilitate forming the circular welds by production methods and assuresa gas tight seal between the ball or spherically-shaped portion of eachcoupling with the curved portions 30 and 32 at the ends of the shell. Itwill be apparent that the couplings 38 and 40 may be arranged in variousangular positions but each of the welds 52 and 66 will be of circularcontour irrespective of the angularities of the couplings with themuffler shell.

FIGURE 4 illustrates a modified configuration for the curved end regionof a muffier shell 68. In this form of construction, the gas inletcoupling or fitting 70 is fashioned with a ball-shaped orspherically-shaped configuration 72, the center 74 of generation of theballshaped portion 72 being displaced laterally from the longitudinalaxis BB of the muffler 68. The curved or dome-shaped portion 76 at the.end region of the muffier shell 68 is fashioned to terminate in acircular edge 78 defining an opening of a dimension to snugly receivethe spherically-shaped exterior configuration 72 of the tubular coupling70. The circular terminal edge 78 of the curved portion 76 of themufiier shell is welded as at 80 to the ball-shaped portion 72throughout its circumference to provide a circular weld.

In the arrangement shown in FIGURE 4, the coupling or fitting 70 may beangularly-arranged with respect to the muflier shell 68 and displacedfrom the axis of the mufiier shell to accommodate particularinstallations of the mufiler with an exhaust system of an internalcombustion engine of an automotive vehicle. The outlet or opening of thecoupling 70 within the muflier shell may be defined by an outwardlyflared terminus or flange 82 to facilitate exhaust gas flow into themufller shell with a minimum of whistling noise.

Disposed in the mufiler shell 68 is a gas passage tube 84 supported by apartition or header 86, the gas passage tube being fashioned with alarge number of small perforations or openings 90 providing acousticcouplings between the gas passage tube and the annular sound attenuatingchamber 88 surrounding the tube.

It is to be understood that the mufiier 63 may be fashioned at itsopposite end to accommodate an outlet coupling secured to a similarlycurved portion of the shell in the same manner as the inlet coupling 70.

FIGURE 5 illustrates a gas inlet coupling 38a having a ball-shapedportion 50a secured by welding 52a to the circular terminal edge of acurved or dome-shaped portion 30a of a 'mufller shell 12a. In this formthe ball configuration 50a terminates in a circular edge 94 lying in aplane substantially normal to the longitudinal axis CC of the mufflershell 12a. The coupling or fitting 38a is similar to the fitting 38,shown in FIGURE 1, but with the portion 96, indicated in broken lines,removed from the portion of the fitting extending into the mufiler shell12a.

Through this arrangement the exhaust gas delivered from the openingdefined by the circular edge 93 is more nearly directed axially of themufiier shell 12a toward the gas passage tube 14a. With the arrangementshown in FIGURE 5 the resistance of deflecting the exhaust gases towardthe gas passage tube 14a is minimized. The fitting 38a is adapted toaccommodate an exhaust pipe (not shown) for conveying exhaust gases intothe muffier. It is to be understood that an outlet fitting of the samecharacter as illustrated ,at 38a may be secured to a curved portion atthe other end of the mufiier shell 12a.

FIGURE 6 illustrates a modified form of the invention wherein a gasconveying coupling provides support for a gas passage tube. The mufflershell 12b is provided with a curved or dome-shaped portion 30bterminating in a circular terminal edge 34b defining an opening.

A tubular coupling or bushing fitting 100 is fashioned with asperically-shaped or ball portion 102 which snugly fits in the openingdefined by the circular edge 34b of the curved end region 3% of themuflier shell. The spherically-shaped or ball-shaped portion 102 isfashioned with a cylindrical extension 104 disposed within the mufflershell 12b.

A gas passage tube 106, disposed in the shell 12b, has an end region 108in telescoping or overlapping relation with the cylindrical portion 104of the coupling or bushing 100. The overlapping portions of the couplingand gas passage tube may be welded together as shown at 110. The gaspassage tube 106 has a large number of small openings 112 which formacoustic couplings with the annular chamber 114 surrounding the gaspassage tube for attenuating sound waves. Through engagement of the endof the gas passage tube with an extension of the coupling 100, one endof the gas passage tube is supported by the coupling or bushing 100.

The other end of the gas passage tube 106 may be supported by apartition, such as a partilion of the character illustrated at 22 in theform of the invention illustrated in FIGURE 1. In assembling thearrangement shown in FIGURE 6, the gas passage tube 106 is Welded to theextension 104 of the coupling or bushing prior to its assembly withinthe muffier shell 12b. In this form, the

axes of the coupling and the gas passage tube 106 are in alignedrelation.

Upon positioning of the ball-shaped portion 102 in the circular openingdefined by the circular edge 34b of the muffler shell, the terminal edge34b of the mufiler shell 12b is welded as at 116 throughout thecircumference of the exterior surface of the spherically-shaped portion102 of the coupling 100 :to form a gas tight joint between the couplingand the muffler shell. The coupling 100 is adapted to accommodate theend region of a conventional exhaust pipe for conveying exhaust gasesinto the mufiler. A coupling similar to the coupling 100 may be mountedin theoutlet region of the muffler shell and the gas passage tubesupported thereby in the manner illustrated in FIGURE 6.

FIGURE 7 illustrates another form of the invention. In this form an endregion of the muffler shell 120 is fashioned with a curved ordome-shaped portion 122 terminating in a circular opening defined by acircular edge 123. Disposed within the mufiler shell 120 is acylindricallyshaped gas passage tube 124 having a large number of smallopenings 125 which form acoustic couplings with an annular chamber 126surrounding the gas passage tube. An end of the gas passage tube isprovided with a spherically-shaped or ball-shaped portion 128 whichsnugly fits within the circular opening defined by the circular edge 123at the end of the muffler shell 120.

The spherically-shaped portion 128 terminates in a circular opening. Atubular coupling or bushing 130 is fashioned with a spherically-shapedor ball-like portion 132, the exterior diameter being of a dimension tosnugly fit the circular opening defined by the terminal edge of thecurved or ball-shaped portion 128 of the gas passage tube.

The circular terminal edge of the ball-shaped portion 128 is welded .asat 134 to the ball shaped portion 132 of the coupling throughout itsperiphery. The terminal edge 123 of the dome-shaped portion 122 of themufi le-r shell 120 is welded as at 136 to the ball-shaped portion 128throughout its periphery.

The circular weldings 134 and 136 provide gas tight or sealed jointsbetween the coupling 130 and the gas passage tube, and between the gaspassage tube and the end region of the muffler shell 120. The coupling130 may be angularly adjusted with respect to the axis of the gaspassage tube 124 as desired and welded in adjusted position. In order toenhance the flow of exhaust gases from the coupling 130 into the gaspassage tube, the end of the coupling within the ball-shaped portion 128of the gas passage tube may be terminated in a circular edge 138 normalto the axis of the gas passage tube as illustrated in the drawings.

The portion 140 of the ball-shaped configuration 132. on the coupling orbushing, illustrated by broken lines, may be removed to facilitatediversion of the gase flowing through the coupling 130 toward the gaspassage tube 124 with a minimum of flow resistance. In the form of theinvention shown in FIGURE 7, an end of the gas passage tube is supportedby an end region of the mufiier shell 120, and the .angularly disposedcoupling or bushing 130, welded to a ball-shaped portion of the gaspassage tube, is thus supported by the gas passage tube.

FIGURE 8 shows a further modification of the invention. In this form themuffler shell 144 is fashioned with a curved or dome-shaped end portion146 terminating in a circular edge 147 defining a circular opening atthe terminus of the dome-shaped portion 146-. A gas inlet coupling orbushing 148 is fashioned with a sphericallyshaped or ball-like portion150 which snugly fits into the circular opening defined by the terminaledge 147, the terminal edge of the dome-shaped portion 146 of themuffler shell being welded as at 152 throughout the periphery of theball-shaped portion 150 to provide a gas tight joint between thecoupling 148 land the muffler shell 144.

Disposed within the mufiler shell 144 is a header or partition 154 whichsupports one end of a cylindrical gas passage tube 156, the latter beingfashioned with a large number of small openings 158 which form acousticcouplings with an annular chamber 160 surrounding the gas passage tube.In the form shown in FIGURE 8, the coupling or bushing 148 is fashionedwith a portion 162 of an internal diameter to snugly receive an endportion of the gas passage tube 156 whereby the inlet end of the gaspassage tube is supported by the coupling or bushing 148. Theoverlapping contiguous regions of the gas passage tube and the coupling148 may be spot-welded together as shown at 164.

The inlet coupling 148 is adapted to telescopingly receive an exhaustpipe (not shown) for conveying exhaust gases into the mufilerconstruction.

An outlet fitting 168 is fashioned with a sphericallyshaped or ballportion 178 which fits in the circular opening defined by a circularedge 171 at the terminus of the curved or dome-shaped region 172 at theoutlet end of the mufller shell. The terminal edge defining the openingreceiving the ball-shaped portion 170 is welded as at 174 throughout theperiphery of the ball-shaped portion to form a gas tight shell or joint.

'FIGURE 9 illustrates a form of the invention wherein the gas passagetube of the mufiler construction is supported by the couplings orbushings at the inlet and outlet ends of the muffler. The muffier shell180 is fashioned with dome-shaped or curved end regions 181 and 182terminating in circular edges 183 and 184 defining circular openings. Aninlet coupling or bushing 185 is fashioned with a spherically-shaped orball-like portion 186 snugly fitting into the circular opening definedby the circular edge 183. Disposed within the mufller shell 180 is a gaspasage tube 188 having small openings 189 forming acoustic couplingswith an annular chamber 190.

The axis of the coupling or bushing 185 is aligned with the longitudinalaxis of the gas passage tube 188, the ballshaped portion 186 of thecoupling being welded as at 192 throughout its periphery to the terminalend or edge of the dome-shaped portion 181 of the muffier. The couplingor bushing 185 is provided with a cylindrical region 194 of reduceddiameter to snugly yet slidably accommodate an end region 195 of the gaspassage tube 188.

The contiguous regions of the cylindrical portion 194 and the gaspassage tube 188 are spot welded together as shown at 196. In thismanner, the inlet coupling or bushing 185 supports one end of the gaspassage tube 188.

A gas outlet coupling or bushing 200 is disposed at the opposite end ofthe mufiler shell and has a sphericallyshaped or ball-like configuration202 extending into a circular opening defined by the circular edge 184-at the terminus of the dome-shaped end 182 of the mutfier shell. Thelongitudinal axis of the coupling 200 is aligned with the axis of thegas passage tube 188. The coupling 200 is fashioned with acylindrically-shaped portion 204 of an internal diameter to snuglyreceive the end region 206 of the gas passage tube 188, the overlappingregions of the cylindrical portion 204 and the end portion 206 of thegas passage tube being spot welded together as at 208.

The ball-shaped portion 202 of the coupling 200 is welded as at 210throughout its periphery to the terminal end of the dome-shaped portion182 to form a gas tight or sealed joint. The outlet coupling 200 isadapted to telescopingly receive a tailpipe or other conventional gasconveying tube (not shown). Thus the respective ends of the gas passagetube 188 are welded to and supported by the couplings or bushings 185and 200' and the couplings in turn welded to the one piece muffier shell180 by the peripheral welds 192 and 210.

It will thus be seen that in all forms of the invention, the weldsbetween the dome-shaped ends of the one piece rnufiier shell and theinlet and outlet couplings or, as shown in FIGURE 7, between aball-shaped end region of the gas passage tube and a couplings arecircular welds irrespective of the angularities of the couplings orbushings with respect to the mufiier shell. By

sears providing a method of construction wherein the welding regions arecircular, high speed production of welding may be attained assuring agas tight mufiier construction.

FIGURE 10 illustrates a construction similar to FIG- URE 5. In thearrangement shown in FIGURE 10, the muffler shell is fashioned with adome-shaped end region 30c. The inlet coupling 380 is formed with aballshaped configuration 500 which extends into the circular openingdefined by the terminal edge of the dome-shaped end region 300 of themufiier shell and is welded to the circular terminal edge as at 526. Agas passage tube 212 is disposed interiorly of the shell 12c and is of asmall diameter whereby the end 214 of the tube 212 extends into theball-shaped configuration 500. The gas passage tube 212 may be supportedby one or more bafiles 216, one being illustrated in FIGURE 10. The wallof the gas passage tube at the right-end side of the bafile 216 isfashioned with a comparatively large number of small openings 218forming acoustic couplings with the annular space between the gaspassage tube 212 and the mufiier shell 12c. By extending the gas passagetube 212 into the ball-shaped configuration 50c, whistling noises causedby the moving exhaust gas stream are substantially reduced.

In the forms of the invention shown in FGURES 1, 2, 4, 5, 7 and 10 thetubular couplings or bushings may be angularly adjusted to accommodatethe angularities of various gas conveying pipes or tubes thus readilyadapting the muifier to various installations without special couplingsfor each installation. In the forms shown in FIGURES 6, 8 and 9, thecouplings may be employed to support one or both ends of a gas passagetube and thereby eliminate one or both partitions or headers in themuiller.

In all forms of muffler construction illustrated herein, the annularspace or region between the gas passage tube and the muffler shell maybe filled with sound absorbing or sound damping material such as fibrousglass or other similar material which is resistant to high temperatures.

It is apparent that, within the scope of the invention, modificationsand different arrangements may be made other than as herein disclosed,and the present disclosure is illustrative merely, the inventioncomprehendnig all variations thereof.

I claim:

1. A mufiier for use with the exhaust system of an internal combustionengine including a one-piece tubular shell having an integral end regionof dome-shaped configuration terminating in a circular edge defining anopening, and a tubular fitting having a spherically-shaped portionextending into the opening and disposed adjacent the circular edge, thecircular edge being joined to the adjacent spherically-shaped portion ofthe tubular fitting by welding to provide a fluid tight joint betweenthe shell and the tubular fitting.

2. The combination according to claim 1 including tubular gas passagemeans mounted within the shell.

3. A muffler for use with the exhaust system of an internal combustionengine including a one-piece tubular shell having an integral smoothlycurved end region of progressively decreasing diameter terminating in acircular edge defining an opening, a tubular coupling member having aspherically-shaped portion extending into the opening and disposedadjacent the circular edge, the circular edge being joined to theadjacent portion of the tubular coupling member by welding to provide afluid tight joint between the shell and the tubular member.

4 The combination according to claim 3 including a gas passage tubemounted within the shell, said gas passage tube having open areasproviding acoustic couplings with a region between the shell and the gaspassage tube.

5. A mufiier for use with the exhaust system of an internal combustionengine including a one-piece tubular shell having integral smoothlycurved end regions of progressively decreasing diameter providingdome-shaped configurations, each configuration terminating in a circularedge defining a circular opening, tubular gas inlet and outlet fittingsfor the respective ends of the shell, each of said fittings having aspherically-shaped portion extending into the adjacent opening, thecircular edges being joined to the adjacent spherically-shaped portionsof the respective fittings by welding to provide fluid tight jointsbetween the shell and the fittings.

6. A muflier for use with exhaust system of an internal combustionengine comprising, in combination, a onepiece tubular shell having anintegral end region of domeshaped configuration terminating in acircular edge defining an opening, tubular means having asphericallyshaped portion, the spherically-shaped portion of the tubularmeans being disposed in the opening and snugly engaging the circularedge, the circular edge at the end of the shell being joined to thespherically-shaped portion of said tubular means by welding the circularedge throughout its circumference to the spherically-shaped portion toprovide a fluid tight joint between the shell and the tubular means.

7. The combination according to claim 6 wherein the tubular means isangularly arranged with respect to the longitudinal axis of the shell.

8. The combination according to claim 6 wherein both end regions of thetubular shell are dome-shaped configurations terminating in circularedges defining openings, and tubular means for each end of the shell,both tubular means having spherically-shaped portions joined by weldingthe circular edges to the spherically-shaped portions.

9. A muffier comprising, in combination, a one-piece thin-walledcylindrically-shaped shell, a gas passage tube of lesser diametermounted within the shell, at least one end region of the shell being ofprogressively reduced diameter providing a dome-like configurationterminating in a circular edge defining an opening, a tubular memberhaving a spherically-shaped portion fitting within the opening andsnugly engaging the circular edge, said tubular member being adapted tobe angularly disposed with respect to the axis of said shell, and fusedmetal bonding the circular edge of said dome-shaped configuration to thespherically-shaped portion of the tubular member throughout a peripheralregion of the spherically-shaped portion forming a fluid tight joint andsecuring the tubular member in angularly disposed position.

10. A mufiler for use with the exhaust system of an internal combustionengine comprising, in combination, a one-piece cylindrically-shapedthin-walled metal shell, the end regions of said shell being ofdome-shaped configuration, each dome-shaped configuration terminating ina circular edge defining an opening, a tubular gas inlet fitting for oneend of said shell, a tubular gas outlet fitting for the other end ofsaid shell, each of said fittings having a spherically-shaped portionextending into the opening at an end of the shell and snugly engagingthe circular edge, said spherically-shaped portions of said fittingsbeing welded to the circular edge regions of dome-shaped portionsdefining the openings to form gas tight joints, and a gas passage tubedisposed within said shell, the wall of said gas passage tube havingsmall openings therein forming acoustic couplings with a spacesurrounding the gas passage tube.

11. The combination recited in claim 10 including a partition in saidshell providing support means for the gas passage tube.

12. The combination according to claim 10 including a partition in saidshell providing support means for an end region of the gas passage tube,the other end of said gas passage tube being in engagement with andsupported by one of said tubular fittings.

13. The combination according to claim 10 wherein the respective ends ofthe gas passage tube are in engagement with said inlet and outletfittings whereby the gas passage tube is supported by said fittings.

14. A mufiier comprising, in combination, a one-piece tubular shell ofsubstantially cylindrical configuration, an end region of said tubularshell being of progressively reduced diameter providing a dome-shapedconfiguration terminating in a circular edge defining an opening, atubular coupling member having a spherically-shaped portion snuglyfitting within said opening, fused metal bonding the circular edgeregion of said dome-shaped configuration to the spherically-shapedconfiguration to form a fluid tight joint, the tubular coupling memberhaving a cylindrical extension Within the shell of lesser diameter thanthe diameter of the exterior surface of the sphericallyshapedconfiguration and integrally joined with the spherically-shapedconfiguration, and a gas passage tube disposed within the shell havingan end region in overlapping relation with said extension providingsupport means for the gas passage tube, said gas passage tube having aplurality of openings in the wall thereof providing acoustic couplingswith the space surrounding the gas passage tube.

15. The method of producing a mufller comprising the steps ofprogressively reducing an end region of a thin walled tubular shell toform a dome-shaped configuration terminating in a circular edge definingan opening, positioning a spherically-shaped portion of a tubularcoupling in the circular opening with the circular edge snugly engagingthe spherically-shaped portion, and welding the circular edge to thespherically-shaped portion throughout its periphery to form a gas tightseal.

16. The method according to claim 15 including the step of adjusting thetubular coupling at an angle with respect to the longitudinal axis ofthe tubular shell prior to welding the circular edge to thespherically-shaped portion.

I References Cited UNITED STATES PATENTS 1,838,249 12/1931 Brown 2852861,972,065 8/1934 Noblitt 18l-48 2,035,923 3/1936 Scarritt 181--482,485,392 10/1949 Leadbetter 18148 2,553,326 5/1951 Manning 18-1-612,598,756 6/1952. Brightly et a1. 18161 2,872,998 2/1959 Tinker 181--613,159,239 12/1964 Andrews 18161 3,274,678 9/1966 Andrews 29471.1

FOREIGN PATENTS 877,911 9/ 1942 France.

ROBERT S. WARD, JR., Primary Examiner.

